package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private IVoucherOrderService proxy;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;

    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }


    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {
        private String queueName = "stream.orders";

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取队列中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1")
                            , StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2))
                            , StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        continue;
                    }
                    // 3.解析消息中的订单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.创建订单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 1.获取pending-list中的订单信息
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1")
                            , StreamReadOptions.empty().count(1)
                            , StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 2.判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        break;
                    }
                    // 3.解析消息中的订单
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 4.创建订单
                    handleVoucherOrder(voucherOrder);
                    // 5.ACK确认
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常", e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }


    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        // 获取锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断是否获取成功
        if (!isLock) {
            log.error("用户已经购买过一次！");
            return;
        }

        try {
            // 获取代理对象
            proxy.creatVoucherOrder(voucherOrder);
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        // 获取用户
        UserDTO user = UserHolder.getUser();
        long orderId = redisIdWorker.nextID("order");
        // 1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT
                , Collections.emptyList()
                , voucherId.toString()
                , user.getId().toString()
                , String.valueOf(orderId)
        );

        // 2.判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            return Result.fail(r == 1 ? "库存不足！" : "用户已经购买过一次！");
        }

        // 获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        // 3.返回订单id
        return Result.ok(orderId);
    }


    @Transactional
    public void creatVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单
        Long userId = voucherOrder.getUserId();
        // 5.1.查询订单
        int count = query()
                .eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
        // 5.2.判断是否存在
        if (count > 0) {
            log.error("用户已经购买过一次！");
            return;
        }
        // 6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId())
                .gt("stock", 0).update();
        if (!success) {
            log.error("库存不足！");
            return;
        }
        // 7.创建订单
        save(voucherOrder);
    }
}
